1. Field of the Invention
The present invention generally relates to a processing circuit and a noise cancelling method thereof, and more particularly, to an image processing circuit and a ringing artifact removing method thereof.
2. Description of Related Art
With advancement of computer technology, digital media have become one of the major instruments for demonstrating creativity and imagination in recent years. According to digital image processing (DIP) principles, analog images are “digitized” before the two-dimensional or the three-dimensional images are processed by computers. The image data are then digitally processed and transmitted to an image output device in form of digital images. After the image output device receives the digital image, the image data are up-sampled. If a low order filter is adopted in the image output device to up-sample the image data, data at high frequency in the digital image are blurred. By contrast, when a high order filter is utilized for up-sampling the image data, the data at high frequency in the digital image can be retained. However, with use of the high order filter for up-sampling the image data, ripples are likely to be formed due to ringing effects. As such, the quality of the ultimately output images is deteriorated.
Generally, ringing artifacts in the ultimately output images are removed by using a low-pass filter. However, the low-pass filter also removes some image details, which results in blurring artifacts. Thereby, a new technique for removing ringing artifacts from the ultimately output image is desired.